Transactions . ections, and additional facts. Having served its purpose, it was, forobvious reasons, and in accordance with usual practice, omitted when the paperwas printed in permanent form in vol. xxviii.—R. W. R. f Mr. Lymans paper, present volume, pp. 88-90. + Trans., xxviii., 694 and 697. § Surveying Instrument*, William Ford Stanley, 2d ed., London, 1895, p. 206. 924 TII K K V()LITI ()X «»!• .M I N B-S URVEYING I XSTK I M EXTS. me,seems inclined to forgive as for having detected an inaccu-racy in lii> otherwise studiously prepared and exhaustive force was given, in my mind,
Transactions . ections, and additional facts. Having served its purpose, it was, forobvious reasons, and in accordance with usual practice, omitted when the paperwas printed in permanent form in vol. xxviii.—R. W. R. f Mr. Lymans paper, present volume, pp. 88-90. + Trans., xxviii., 694 and 697. § Surveying Instrument*, William Ford Stanley, 2d ed., London, 1895, p. 206. 924 TII K K V()LITI ()X «»!• .M I N B-S URVEYING I XSTK I M EXTS. me,seems inclined to forgive as for having detected an inaccu-racy in lii> otherwise studiously prepared and exhaustive force was given, in my mind, to this citation, when Ifound in Adamss Geometrical Essays, published sis years previ-ously (1797), a description and cul of a miniature theodolite,herewith reproduced in Fig. 167. rl nis is a 4-inch model whichAdams designed in 1791, and at least suggests the possibilityof making a small transit-instrument by slightly increasing theheight of the standards ;is they occur in the contemporaneous Fig. Adamss Miniature Theodolite. instrument shown in Fig. 16 (Trans., xxviii., 696), and by sub-stituting a better-proportioned telescope. The telescope rested in a sort of cradle, and could be re-versed, end for end, by opening the clips, a, a. The verticalarc was set concentric with the axis of revolution; and while,by the old-fashioned rack-and-pinion screw, the telescope couldbe made to move through an arc of onlv from 30° to 40° aboveand below the horizon, I consider this, in some respects, themost perfect of old English portable instruments. Dr. Raymond has called attention to the fact that the originalastronomical transit-instrument was the invention of Iioemer
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Keywords: ., bo, bookcentury1800, bookdecade1870, booksubjectmineralindustries
